module Path

  # == Path::Name
  #
  # Pathname represents a pathname which locates a file in a filesystem.
  # The pathname depends on OS: Unix, Windows, etc.
  # Pathname library works with pathnames of local OS.
  # However non-Unix pathnames are supported experimentally.
  #
  # It does not represent the file itself.
  # A Pathname can be relative or absolute.  It's not until you try to
  # reference the file that it even matters whether the file exists or not.
  #
  # Pathname is immutable.  It has no method for destructive update.
  #
  # The value of this class is to manipulate file path information in a neater
  # way than standard Ruby provides.  The examples below demonstrate the
  # difference.  *All* functionality from File, FileTest, and some from Dir and
  # FileUtils is included, in an unsurprising way.  It is essentially a facade for
  # all of these, and more.
  #
  # == Examples
  #
  # === Example 1: Using Pathname
  #
  #   require 'pathname'
  #   pn = Pathname.new("/usr/bin/ruby")
  #   size = pn.size              # 27662
  #   isdir = pn.directory?       # false
  #   dir  = pn.dirname           # Pathname:/usr/bin
  #   base = pn.basename          # Pathname:ruby
  #   dir, base = pn.split        # [Pathname:/usr/bin, Pathname:ruby]
  #   data = pn.read
  #   pn.open { |f| _ }
  #   pn.each_line { |line| _ }
  #
  # === Example 2: Using standard Ruby
  #
  #   pn = "/usr/bin/ruby"
  #   size = File.size(pn)        # 27662
  #   isdir = File.directory?(pn) # false
  #   dir  = File.dirname(pn)     # "/usr/bin"
  #   base = File.basename(pn)    # "ruby"
  #   dir, base = File.split(pn)  # ["/usr/bin", "ruby"]
  #   data = File.read(pn)
  #   File.open(pn) { |f| _ }
  #   File.foreach(pn) { |line| _ }
  #
  # === Example 3: Special features
  #
  #   p1 = Pathname.new("/usr/lib")   # Pathname:/usr/lib
  #   p2 = p1 + "ruby/1.8"            # Pathname:/usr/lib/ruby/1.8
  #   p3 = p1.parent                  # Pathname:/usr
  #   p4 = p2.relative_path_from(p3)  # Pathname:lib/ruby/1.8
  #   pwd = Pathname.pwd              # Pathname:/home/gavin
  #   pwd.absolute?                   # true
  #   p5 = Pathname.new "."           # Pathname:.
  #   p5 = p5 + "music/../articles"   # Pathname:music/../articles
  #   p5.cleanpath                    # Pathname:articles
  #   p5.realpath                     # Pathname:/home/gavin/articles
  #   p5.children                     # [Pathname:/home/gavin/articles/linux, ...]
  #
  # == Breakdown of functionality
  #
  # === Core methods
  #
  # These methods are effectively manipulating a String, because that's
  # all a path is.  Except for #mountpoint?, #children, #each_child,
  # #realdirpath and #realpath, they don't access the filesystem.
  #
  # - +
  # - #join
  # - #parent
  # - #root?
  # - #absolute?
  # - #relative?
  # - #relative_path_from
  # - #each_filename
  # - #cleanpath
  # - #realpath
  # - #realdirpath
  # - #children
  # - #each_child
  # - #mountpoint?
  #
  # === File status predicate methods
  #
  # These methods are a facade for FileTest:
  # - #blockdev?
  # - #chardev?
  # - #directory?
  # - #executable?
  # - #executable_real?
  # - #exist?
  # - #file?
  # - #grpowned?
  # - #owned?
  # - #pipe?
  # - #readable?
  # - #world_readable?
  # - #readable_real?
  # - #setgid?
  # - #setuid?
  # - #size
  # - #size?
  # - #socket?
  # - #sticky?
  # - #symlink?
  # - #writable?
  # - #world_writable?
  # - #writable_real?
  # - #zero?
  #
  # === File property and manipulation methods
  #
  # These methods are a facade for File:
  # - #atime
  # - #ctime
  # - #mtime
  # - #chmod(mode)
  # - #lchmod(mode)
  # - #chown(owner, group)
  # - #lchown(owner, group)
  # - #fnmatch(pattern, *args)
  # - #fnmatch?(pattern, *args)
  # - #ftype
  # - #make_link(old)
  # - #open(*args, &block)
  # - #readlink
  # - #rename(to)
  # - #stat
  # - #lstat
  # - #make_symlink(old)
  # - #truncate(length)
  # - #utime(atime, mtime)
  # - #basename(*args)
  # - #dirname
  # - #extname
  # - #expand_path(*args)
  # - #split
  #
  # === Directory methods
  #
  # These methods are a facade for Dir:
  # - Pathname.glob(*args)
  # - Pathname.getwd / Pathname.pwd
  # - #rmdir
  # - #entries
  # - #each_entry(&block)
  # - #mkdir(*args)
  # - #opendir(*args)
  #
  # === IO
  #
  # These methods are a facade for IO:
  # - #each_line(*args, &block)
  # - #read(*args)
  # - #binread(*args)
  # - #readlines(*args)
  # - #sysopen(*args)
  #
  # === Utilities
  #
  # These methods are a mixture of Find, FileUtils, and others:
  # - #find(&block)
  # - #mkpath
  # - #rmtree
  # - #unlink / #delete
  #
  #
  # == Method documentation
  #
  # As the above section shows, most of the methods in Pathname are facades.  The
  # documentation for these methods generally just says, for instance, "See
  # FileTest.writable?", as you should be familiar with the original method
  # anyway, and its documentation (e.g. through +ri+) will contain more
  # information.  In some cases, a brief description will follow.
  #
  # = path/name.rb
  #
  # Object-Oriented Pathname Class
  #
  # Author:: Tanaka Akira <akr@m17n.org>
  # Documentation:: Author and Gavin Sinclair
  #
  # <tt>pathname.rb</tt> is distributed with Ruby since 1.8.0.
  #
  class Name

    # :stopdoc:
    if RUBY_VERSION < "1.9"
      TO_PATH = :to_str
    else
      # to_path is implemented so Pathname objects are usable with File.open, etc.
      TO_PATH = :to_path
    end

    SAME_PATHS = if File::FNM_SYSCASE
      proc {|a, b| a.casecmp(b).zero?}
    else
      proc {|a, b| a == b}
    end

    # :startdoc:

    #
    # Create a Pathname object from the given String (or String-like object).
    # If +path+ contains a NUL character (<tt>\0</tt>), an ArgumentError is raised.
    #
    def initialize(path)
      path = path.__send__(TO_PATH) if path.respond_to? TO_PATH
      @path = path.dup

      if /\0/ =~ @path
        raise ArgumentError, "pathname contains \\0: #{@path.inspect}"
      end

      self.taint if @path.tainted?
    end

    def freeze() super; @path.freeze; self end
    def taint() super; @path.taint; self end
    def untaint() super; @path.untaint; self end

    #
    # Compare this pathname with +other+.  The comparison is string-based.
    # Be aware that two different paths (<tt>foo.txt</tt> and <tt>./foo.txt</tt>)
    # can refer to the same file.
    #
    def ==(other)
      return false unless Pathname === other
      other.to_s == @path
    end
    alias === ==
    alias eql? ==

    # Provides for comparing pathnames, case-sensitively.
    def <=>(other)
      return nil unless Pathname === other
      @path.tr('/', "\0") <=> other.to_s.tr('/', "\0")
    end

    def hash # :nodoc:
      @path.hash
    end

    # Return the path as a String.
    def to_s
      @path.dup
    end

    # to_path is implemented so Pathname objects are usable with File.open, etc.
    alias_method TO_PATH, :to_s

    def inspect # :nodoc:
      "#<#{self.class}:#{@path}>"
    end

    # Return a pathname which is substituted by String#sub.
    def sub(pattern, *rest, &block)
      if block
        path = @path.sub(pattern, *rest) {|*args|
          begin
            old = Thread.current[:pathname_sub_matchdata]
            Thread.current[:pathname_sub_matchdata] = $~
            eval("$~ = Thread.current[:pathname_sub_matchdata]", block.binding)
          ensure
            Thread.current[:pathname_sub_matchdata] = old
          end
          yield(*args)
        }
      else
        path = @path.sub(pattern, *rest)
      end
      self.class.new(path)
    end

    if File::ALT_SEPARATOR
      SEPARATOR_LIST = "#{Regexp.quote File::ALT_SEPARATOR}#{Regexp.quote File::SEPARATOR}"
      SEPARATOR_PAT = /[#{SEPARATOR_LIST}]/
    else
      SEPARATOR_LIST = "#{Regexp.quote File::SEPARATOR}"
      SEPARATOR_PAT = /#{Regexp.quote File::SEPARATOR}/
    end

    # Return a pathname which the extension of the basename is substituted by
    # <i>repl</i>.
    #
    # If self has no extension part, <i>repl</i> is appended.
    def sub_ext(repl)
      ext = File.extname(@path)
      self.class.new(@path.chomp(ext) + repl)
    end

    # chop_basename(path) -> [pre-basename, basename] or nil
    def chop_basename(path)
      base = File.basename(path)
      if /\A#{SEPARATOR_PAT}?\z/o =~ base
        return nil
      else
        return path[0, path.rindex(base)], base
      end
    end
    private :chop_basename

    # split_names(path) -> prefix, [name, ...]
    def split_names(path)
      names = []
      while r = chop_basename(path)
        path, basename = r
        names.unshift basename
      end
      return path, names
    end
    private :split_names

    def prepend_prefix(prefix, relpath)
      if relpath.empty?
        File.dirname(prefix)
      elsif /#{SEPARATOR_PAT}/o =~ prefix
        prefix = File.dirname(prefix)
        prefix = File.join(prefix, "") if File.basename(prefix + 'a') != 'a'
        prefix + relpath
      else
        prefix + relpath
      end
    end
    private :prepend_prefix

    # Returns clean pathname of +self+ with consecutive slashes and useless dots
    # removed.  The filesystem is not accessed.
    #
    # If +consider_symlink+ is +true+, then a more conservative algorithm is used
    # to avoid breaking symbolic linkages.  This may retain more <tt>..</tt>
    # entries than absolutely necessary, but without accessing the filesystem,
    # this can't be avoided.  See #realpath.
    #
    def cleanpath(consider_symlink=false)
      if consider_symlink
        cleanpath_conservative
      else
        cleanpath_aggressive
      end
    end

    #
    # Clean the path simply by resolving and removing excess "." and ".." entries.
    # Nothing more, nothing less.
    #
    def cleanpath_aggressive
      path = @path
      names = []
      pre = path
      while r = chop_basename(pre)
        pre, base = r
        case base
        when '.'
        when '..'
          names.unshift base
        else
          if names[0] == '..'
            names.shift
          else
            names.unshift base
          end
        end
      end
      if /#{SEPARATOR_PAT}/o =~ File.basename(pre)
        names.shift while names[0] == '..'
      end
      self.class.new(prepend_prefix(pre, File.join(*names)))
    end
    private :cleanpath_aggressive

    # has_trailing_separator?(path) -> bool
    def has_trailing_separator?(path)
      if r = chop_basename(path)
        pre, basename = r
        pre.length + basename.length < path.length
      else
        false
      end
    end
    private :has_trailing_separator?

    # add_trailing_separator(path) -> path
    def add_trailing_separator(path)
      if File.basename(path + 'a') == 'a'
        path
      else
        File.join(path, "") # xxx: Is File.join is appropriate to add separator?
      end
    end
    private :add_trailing_separator

    def del_trailing_separator(path)
      if r = chop_basename(path)
        pre, basename = r
        pre + basename
      elsif /#{SEPARATOR_PAT}+\z/o =~ path
        $` + File.dirname(path)[/#{SEPARATOR_PAT}*\z/o]
      else
        path
      end
    end
    private :del_trailing_separator

    def cleanpath_conservative
      path = @path
      names = []
      pre = path
      while r = chop_basename(pre)
        pre, base = r
        names.unshift base if base != '.'
      end
      if /#{SEPARATOR_PAT}/o =~ File.basename(pre)
        names.shift while names[0] == '..'
      end
      if names.empty?
        self.class.new(File.dirname(pre))
      else
        if names.last != '..' && File.basename(path) == '.'
          names << '.'
        end
        result = prepend_prefix(pre, File.join(*names))
        if /\A(?:\.|\.\.)\z/ !~ names.last && has_trailing_separator?(path)
          self.class.new(add_trailing_separator(result))
        else
          self.class.new(result)
        end
      end
    end
    private :cleanpath_conservative

    def realpath_rec(prefix, unresolved, h, strict, last = true)
      resolved = []
      until unresolved.empty?
        n = unresolved.shift
        if n == '.'
          next
        elsif n == '..'
          resolved.pop
        else
          path = prepend_prefix(prefix, File.join(*(resolved + [n])))
          if h.include? path
            if h[path] == :resolving
              raise Errno::ELOOP.new(path)
            else
              prefix, *resolved = h[path]
            end
          else
            begin
              s = File.lstat(path)
            rescue Errno::ENOENT => e
              raise e if strict || !last || !unresolved.empty?
              resolved << n
              break
            end
            if s.symlink?
              h[path] = :resolving
              link_prefix, link_names = split_names(File.readlink(path))
              if link_prefix == ''
                prefix, *resolved = h[path] = realpath_rec(prefix, resolved + link_names, h, strict, unresolved.empty?)
              else
                prefix, *resolved = h[path] = realpath_rec(link_prefix, link_names, h, strict, unresolved.empty?)
              end
            else
              resolved << n
              h[path] = [prefix, *resolved]
            end
          end
        end
      end
      return prefix, *resolved
    end
    private :realpath_rec

    def real_path_internal(strict = false)
      path = @path
      prefix, names = split_names(path)
      if prefix == ''
        prefix, names2 = split_names(Dir.pwd)
        names = names2 + names
      end
      prefix, *names = realpath_rec(prefix, names, {}, strict)
      self.class.new(prepend_prefix(prefix, File.join(*names)))
    end
    private :real_path_internal

    #
    # Returns the real (absolute) pathname of +self+ in the actual
    # filesystem not containing symlinks or useless dots.
    #
    # All components of the pathname must exist when this method is
    # called.
    #
    def realpath
      real_path_internal(true)
    end

    #
    # Returns the real (absolute) pathname of +self+ in the actual filesystem.
    # The real pathname doesn't contain symlinks or useless dots.
    #
    # The last component of the real pathname can be nonexistent.
    #
    def realdirpath
      real_path_internal(false)
    end

    # #parent returns the parent directory.
    #
    # This is same as <tt>self + '..'</tt>.
    def parent
      self + '..'
    end

    # #mountpoint? returns +true+ if <tt>self</tt> points to a mountpoint.
    def mountpoint?
      begin
        stat1 = self.lstat
        stat2 = self.parent.lstat
        stat1.dev == stat2.dev && stat1.ino == stat2.ino ||
          stat1.dev != stat2.dev
      rescue Errno::ENOENT
        false
      end
    end

    #
    # #root? is a predicate for root directories.  I.e. it returns +true+ if the
    # pathname consists of consecutive slashes.
    #
    # It doesn't access actual filesystem.  So it may return +false+ for some
    # pathnames which points to roots such as <tt>/usr/..</tt>.
    #
    def root?
      !!(chop_basename(@path) == nil && /#{SEPARATOR_PAT}/o =~ @path)
    end

    # Predicate method for testing whether a path is absolute.
    # It returns +true+ if the pathname begins with a slash.
    def absolute?
      !relative?
    end

    # The opposite of #absolute?
    def relative?
      path = @path
      while r = chop_basename(path)
        path, basename = r
      end
      path == ''
    end

    #
    # Iterates over each component of the path.
    #
    #   Pathname.new("/usr/bin/ruby").each_filename {|filename| ... }
    #     # yields "usr", "bin", and "ruby".
    #
    def each_filename # :yield: filename
      return to_enum(__method__) unless block_given?
      prefix, names = split_names(@path)
      names.each {|filename| yield filename }
      nil
    end

    # Iterates over and yields a new Pathname object
    # for each element in the given path in descending order.
    #
    #  Pathname.new('/path/to/some/file.rb').descend {|v| p v}
    #     #<Pathname:/>
    #     #<Pathname:/path>
    #     #<Pathname:/path/to>
    #     #<Pathname:/path/to/some>
    #     #<Pathname:/path/to/some/file.rb>
    #
    #  Pathname.new('path/to/some/file.rb').descend {|v| p v}
    #     #<Pathname:path>
    #     #<Pathname:path/to>
    #     #<Pathname:path/to/some>
    #     #<Pathname:path/to/some/file.rb>
    #
    # It doesn't access actual filesystem.
    #
    # This method is available since 1.8.5.
    #
    def descend
      vs = []
      ascend {|v| vs << v }
      vs.reverse_each {|v| yield v }
      nil
    end

    # Iterates over and yields a new Pathname object
    # for each element in the given path in ascending order.
    #
    #  Pathname.new('/path/to/some/file.rb').ascend {|v| p v}
    #     #<Pathname:/path/to/some/file.rb>
    #     #<Pathname:/path/to/some>
    #     #<Pathname:/path/to>
    #     #<Pathname:/path>
    #     #<Pathname:/>
    #
    #  Pathname.new('path/to/some/file.rb').ascend {|v| p v}
    #     #<Pathname:path/to/some/file.rb>
    #     #<Pathname:path/to/some>
    #     #<Pathname:path/to>
    #     #<Pathname:path>
    #
    # It doesn't access actual filesystem.
    #
    # This method is available since 1.8.5.
    #
    def ascend
      path = @path
      yield self
      while r = chop_basename(path)
        path, name = r
        break if path.empty?
        yield self.class.new(del_trailing_separator(path))
      end
    end

    #
    # Pathname#+ appends a pathname fragment to this one to produce a new Pathname
    # object.
    #
    #   p1 = Pathname.new("/usr")      # Pathname:/usr
    #   p2 = p1 + "bin/ruby"           # Pathname:/usr/bin/ruby
    #   p3 = p1 + "/etc/passwd"        # Pathname:/etc/passwd
    #
    # This method doesn't access the file system; it is pure string manipulation.
    #
    def +(other)
      other = Pathname.new(other) unless Pathname === other
      Pathname.new(plus(@path, other.to_s))
    end

    def plus(path1, path2) # -> path
      prefix2 = path2
      index_list2 = []
      basename_list2 = []
      while r2 = chop_basename(prefix2)
        prefix2, basename2 = r2
        index_list2.unshift prefix2.length
        basename_list2.unshift basename2
      end
      return path2 if prefix2 != ''
      prefix1 = path1
      while true
        while !basename_list2.empty? && basename_list2.first == '.'
          index_list2.shift
          basename_list2.shift
        end
        break unless r1 = chop_basename(prefix1)
        prefix1, basename1 = r1
        next if basename1 == '.'
        if basename1 == '..' || basename_list2.empty? || basename_list2.first != '..'
          prefix1 = prefix1 + basename1
          break
        end
        index_list2.shift
        basename_list2.shift
      end
      r1 = chop_basename(prefix1)
      if !r1 && /#{SEPARATOR_PAT}/o =~ File.basename(prefix1)
        while !basename_list2.empty? && basename_list2.first == '..'
          index_list2.shift
          basename_list2.shift
        end
      end
      if !basename_list2.empty?
        suffix2 = path2[index_list2.first..-1]
        r1 ? File.join(prefix1, suffix2) : prefix1 + suffix2
      else
        r1 ? prefix1 : File.dirname(prefix1)
      end
    end
    private :plus

    #
    # Pathname#join joins pathnames.
    #
    # <tt>path0.join(path1, ..., pathN)</tt> is the same as
    # <tt>path0 + path1 + ... + pathN</tt>.
    #
    def join(*args)
      args.unshift self
      result = args.pop
      result = Pathname.new(result) unless Pathname === result
      return result if result.absolute?
      args.reverse_each {|arg|
        arg = Pathname.new(arg) unless Pathname === arg
        result = arg + result
        return result if result.absolute?
      }
      result
    end

    #
    # Returns the children of the directory (files and subdirectories, not
    # recursive) as an array of Pathname objects.  By default, the returned
    # pathnames will have enough information to access the files.  If you set
    # +with_directory+ to +false+, then the returned pathnames will contain the
    # filename only.
    #
    # For example:
    #   pn = Pathname("/usr/lib/ruby/1.8")
    #   pn.children
    #       # -> [ Pathname:/usr/lib/ruby/1.8/English.rb,
    #              Pathname:/usr/lib/ruby/1.8/Env.rb,
    #              Pathname:/usr/lib/ruby/1.8/abbrev.rb, ... ]
    #   pn.children(false)
    #       # -> [ Pathname:English.rb, Pathname:Env.rb, Pathname:abbrev.rb, ... ]
    #
    # Note that the result never contain the entries <tt>.</tt> and <tt>..</tt> in
    # the directory because they are not children.
    #
    # This method has existed since 1.8.1.
    #
    def children(with_directory=true)
      with_directory = false if @path == '.'
      result = []
      Dir.foreach(@path) {|e|
        next if e == '.' || e == '..'
        if with_directory
          result << self.class.new(File.join(@path, e))
        else
          result << self.class.new(e)
        end
      }
      result
    end

    # Iterates over the children of the directory
    # (files and subdirectories, not recursive).
    # It yields Pathname object for each child.
    # By default, the yielded pathnames will have enough information to access the files.
    # If you set +with_directory+ to +false+, then the returned pathnames will contain the filename only.
    #
    #   Pathname("/usr/local").each_child {|f| p f }
    #   #=> #<Pathname:/usr/local/share>
    #   #   #<Pathname:/usr/local/bin>
    #   #   #<Pathname:/usr/local/games>
    #   #   #<Pathname:/usr/local/lib>
    #   #   #<Pathname:/usr/local/include>
    #   #   #<Pathname:/usr/local/sbin>
    #   #   #<Pathname:/usr/local/src>
    #   #   #<Pathname:/usr/local/man>
    #
    #   Pathname("/usr/local").each_child(false) {|f| p f }
    #   #=> #<Pathname:share>
    #   #   #<Pathname:bin>
    #   #   #<Pathname:games>
    #   #   #<Pathname:lib>
    #   #   #<Pathname:include>
    #   #   #<Pathname:sbin>
    #   #   #<Pathname:src>
    #   #   #<Pathname:man>
    #
    def each_child(with_directory=true, &b)
      children(with_directory).each(&b)
    end

    #
    # #relative_path_from returns a relative path from the argument to the
    # receiver.  If +self+ is absolute, the argument must be absolute too.  If
    # +self+ is relative, the argument must be relative too.
    #
    # #relative_path_from doesn't access the filesystem.  It assumes no symlinks.
    #
    # ArgumentError is raised when it cannot find a relative path.
    #
    # This method has existed since 1.8.1.
    #
    def relative_path_from(base_directory)
      dest_directory = self.cleanpath.to_s
      base_directory = base_directory.cleanpath.to_s
      dest_prefix = dest_directory
      dest_names = []
      while r = chop_basename(dest_prefix)
        dest_prefix, basename = r
        dest_names.unshift basename if basename != '.'
      end
      base_prefix = base_directory
      base_names = []
      while r = chop_basename(base_prefix)
        base_prefix, basename = r
        base_names.unshift basename if basename != '.'
      end
      unless SAME_PATHS[dest_prefix, base_prefix]
        raise ArgumentError, "different prefix: #{dest_prefix.inspect} and #{base_directory.inspect}"
      end
      while !dest_names.empty? &&
            !base_names.empty? &&
            SAME_PATHS[dest_names.first, base_names.first]
        dest_names.shift
        base_names.shift
      end
      if base_names.include? '..'
        raise ArgumentError, "base_directory has ..: #{base_directory.inspect}"
      end
      base_names.fill('..')
      relpath_names = base_names + dest_names
      if relpath_names.empty?
        Pathname.new('.')
      else
        Pathname.new(File.join(*relpath_names))
      end
    end
  end

  class Pathname    # * IO *
    #
    # #each_line iterates over the line in the file.  It yields a String object
    # for each line.
    #
    # This method has existed since 1.8.1.
    #
    def each_line(*args, &block) # :yield: line
      IO.foreach(@path, *args, &block)
    end

    # See <tt>IO.read</tt>.  Returns all data from the file, or the first +N+ bytes
    # if specified.
    def read(*args) IO.read(@path, *args) end

    # See <tt>IO.binread</tt>.  Returns all the bytes from the file, or the first +N+
    # if specified.
    def binread(*args) IO.binread(@path, *args) end

    # See <tt>IO.readlines</tt>.  Returns all the lines from the file.
    def readlines(*args) IO.readlines(@path, *args) end

    # See <tt>IO.sysopen</tt>.
    def sysopen(*args) IO.sysopen(@path, *args) end
  end


  class Pathname    # * File *

    # See <tt>File.atime</tt>.  Returns last access time.
    def atime() File.atime(@path) end

    # See <tt>File.ctime</tt>.  Returns last (directory entry, not file) change time.
    def ctime() File.ctime(@path) end

    # See <tt>File.mtime</tt>.  Returns last modification time.
    def mtime() File.mtime(@path) end

    # See <tt>File.chmod</tt>.  Changes permissions.
    def chmod(mode) File.chmod(mode, @path) end

    # See <tt>File.lchmod</tt>.
    def lchmod(mode) File.lchmod(mode, @path) end

    # See <tt>File.chown</tt>.  Change owner and group of file.
    def chown(owner, group) File.chown(owner, group, @path) end

    # See <tt>File.lchown</tt>.
    def lchown(owner, group) File.lchown(owner, group, @path) end

    # See <tt>File.fnmatch</tt>.  Return +true+ if the receiver matches the given
    # pattern.
    def fnmatch(pattern, *args) File.fnmatch(pattern, @path, *args) end

    # See <tt>File.fnmatch?</tt> (same as #fnmatch).
    def fnmatch?(pattern, *args) File.fnmatch?(pattern, @path, *args) end

    # See <tt>File.ftype</tt>.  Returns "type" of file ("file", "directory",
    # etc).
    def ftype() File.ftype(@path) end

    # See <tt>File.link</tt>.  Creates a hard link.
    def make_link(old) File.link(old, @path) end

    # See <tt>File.open</tt>.  Opens the file for reading or writing.
    def open(*args, &block) # :yield: file
      File.open(@path, *args, &block)
    end

    # See <tt>File.readlink</tt>.  Read symbolic link.
    def readlink() self.class.new(File.readlink(@path)) end

    # See <tt>File.rename</tt>.  Rename the file.
    def rename(to) File.rename(@path, to) end

    # See <tt>File.stat</tt>.  Returns a <tt>File::Stat</tt> object.
    def stat() File.stat(@path) end

    # See <tt>File.lstat</tt>.
    def lstat() File.lstat(@path) end

    # See <tt>File.symlink</tt>.  Creates a symbolic link.
    def make_symlink(old) File.symlink(old, @path) end

    # See <tt>File.truncate</tt>.  Truncate the file to +length+ bytes.
    def truncate(length) File.truncate(@path, length) end

    # See <tt>File.utime</tt>.  Update the access and modification times.
    def utime(atime, mtime) File.utime(atime, mtime, @path) end

    # See <tt>File.basename</tt>.  Returns the last component of the path.
    def basename(*args) self.class.new(File.basename(@path, *args)) end

    # See <tt>File.dirname</tt>.  Returns all but the last component of the path.
    def dirname() self.class.new(File.dirname(@path)) end

    # See <tt>File.extname</tt>.  Returns the file's extension.
    def extname() File.extname(@path) end

    # See <tt>File.expand_path</tt>.
    def expand_path(*args) self.class.new(File.expand_path(@path, *args)) end

    # See <tt>File.split</tt>.  Returns the #dirname and the #basename in an
    # Array.
    def split() File.split(@path).map {|f| self.class.new(f) } end
  end


  class Pathname    # * FileTest *

    # See <tt>FileTest.blockdev?</tt>.
    def blockdev?() FileTest.blockdev?(@path) end

    # See <tt>FileTest.chardev?</tt>.
    def chardev?() FileTest.chardev?(@path) end

    # See <tt>FileTest.executable?</tt>.
    def executable?() FileTest.executable?(@path) end

    # See <tt>FileTest.executable_real?</tt>.
    def executable_real?() FileTest.executable_real?(@path) end

    # See <tt>FileTest.exist?</tt>.
    def exist?() FileTest.exist?(@path) end

    # See <tt>FileTest.grpowned?</tt>.
    def grpowned?() FileTest.grpowned?(@path) end

    # See <tt>FileTest.directory?</tt>.
    def directory?() FileTest.directory?(@path) end

    # See <tt>FileTest.file?</tt>.
    def file?() FileTest.file?(@path) end

    # See <tt>FileTest.pipe?</tt>.
    def pipe?() FileTest.pipe?(@path) end

    # See <tt>FileTest.socket?</tt>.
    def socket?() FileTest.socket?(@path) end

    # See <tt>FileTest.owned?</tt>.
    def owned?() FileTest.owned?(@path) end

    # See <tt>FileTest.readable?</tt>.
    def readable?() FileTest.readable?(@path) end

    # See <tt>FileTest.world_readable?</tt>.
    def world_readable?() FileTest.world_readable?(@path) end

    # See <tt>FileTest.readable_real?</tt>.
    def readable_real?() FileTest.readable_real?(@path) end

    # See <tt>FileTest.setuid?</tt>.
    def setuid?() FileTest.setuid?(@path) end

    # See <tt>FileTest.setgid?</tt>.
    def setgid?() FileTest.setgid?(@path) end

    # See <tt>FileTest.size</tt>.
    def size() FileTest.size(@path) end

    # See <tt>FileTest.size?</tt>.
    def size?() FileTest.size?(@path) end

    # See <tt>FileTest.sticky?</tt>.
    def sticky?() FileTest.sticky?(@path) end

    # See <tt>FileTest.symlink?</tt>.
    def symlink?() FileTest.symlink?(@path) end

    # See <tt>FileTest.writable?</tt>.
    def writable?() FileTest.writable?(@path) end

    # See <tt>FileTest.world_writable?</tt>.
    def world_writable?() FileTest.world_writable?(@path) end

    # See <tt>FileTest.writable_real?</tt>.
    def writable_real?() FileTest.writable_real?(@path) end

    # See <tt>FileTest.zero?</tt>.
    def zero?() FileTest.zero?(@path) end
  end


  class Pathname    # * Dir *
    # See <tt>Dir.glob</tt>.  Returns or yields Pathname objects.
    def Pathname.glob(*args) # :yield: pathname
      if block_given?
        Dir.glob(*args) {|f| yield self.new(f) }
      else
        Dir.glob(*args).map {|f| self.new(f) }
      end
    end

    # See <tt>Dir.getwd</tt>.  Returns the current working directory as a Pathname.
    def Pathname.getwd() self.new(Dir.getwd) end
    class << self; alias pwd getwd end

    # Return the entries (files and subdirectories) in the directory, each as a
    # Pathname object.
    def entries() Dir.entries(@path).map {|f| self.class.new(f) } end

    # Iterates over the entries (files and subdirectories) in the directory.  It
    # yields a Pathname object for each entry.
    #
    # This method has existed since 1.8.1.
    def each_entry(&block) # :yield: pathname
      Dir.foreach(@path) {|f| yield self.class.new(f) }
    end

    # See <tt>Dir.mkdir</tt>.  Create the referenced directory.
    def mkdir(*args) Dir.mkdir(@path, *args) end

    # See <tt>Dir.rmdir</tt>.  Remove the referenced directory.
    def rmdir() Dir.rmdir(@path) end

    # See <tt>Dir.open</tt>.
    def opendir(&block) # :yield: dir
      Dir.open(@path, &block)
    end
  end


  class Pathname    # * Find *
    #
    # Pathname#find is an iterator to traverse a directory tree in a depth first
    # manner.  It yields a Pathname for each file under "this" directory.
    #
    # Since it is implemented by <tt>find.rb</tt>, <tt>Find.prune</tt> can be used
    # to control the traverse.
    #
    # If +self+ is <tt>.</tt>, yielded pathnames begin with a filename in the
    # current directory, not <tt>./</tt>.
    #
    def find(&block) # :yield: pathname
      require 'find'
      if @path == '.'
        Find.find(@path) {|f| yield self.class.new(f.sub(%r{\A\./}, '')) }
      else
        Find.find(@path) {|f| yield self.class.new(f) }
      end
    end
  end


  class Pathname    # * FileUtils *
    # See <tt>FileUtils.mkpath</tt>.  Creates a full path, including any
    # intermediate directories that don't yet exist.
    def mkpath
      require 'fileutils'
      FileUtils.mkpath(@path)
      nil
    end

    # See <tt>FileUtils.rm_r</tt>.  Deletes a directory and all beneath it.
    def rmtree
      # The name "rmtree" is borrowed from File::Path of Perl.
      # File::Path provides "mkpath" and "rmtree".
      require 'fileutils'
      FileUtils.rm_r(@path)
      nil
    end
  end


  class Pathname    # * mixed *
    # Removes a file or directory, using <tt>File.unlink</tt> or
    # <tt>Dir.unlink</tt> as necessary.
    def unlink()
      begin
        Dir.unlink @path
      rescue Errno::ENOTDIR
        File.unlink @path
      end
    end
    alias delete unlink
  end

  class Pathname
    undef =~
  end

  module Kernel
    # create a pathname object.
    #
    # This method is available since 1.8.5.
    def Pathname(path) # :doc:
      Pathname.new(path)
    end
    private :Pathname
  end

end
